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Matera C, Papotto C, Dallanoce C, De Amici M. Advances in small molecule selective ligands for heteromeric nicotinic acetylcholine receptors. Pharmacol Res 2023; 194:106813. [PMID: 37302724 DOI: 10.1016/j.phrs.2023.106813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/26/2023] [Accepted: 06/02/2023] [Indexed: 06/13/2023]
Abstract
The study of nicotinic acetylcholine receptors (nAChRs) has significantly progressed in the last decade, due to a) the improved techniques available for structural studies; b) the identification of ligands interacting at orthosteric and allosteric recognition sites on the nAChR proteins, able to tune channel conformational states; c) the better functional characterization of receptor subtypes/subunits and their therapeutic potential; d) the availability of novel pharmacological agents able to activate or block nicotinic-mediated cholinergic responses with subtype or stoichiometry selectivity. The copious literature on nAChRs is related to the pharmacological profile of new, promising subtype selective derivatives as well as the encouraging preclinical and early clinical evaluation of known ligands. However, recently approved therapeutic derivatives are still missing, and examples of ligands discontinued in advanced CNS clinical trials include drug candidates acting at both neuronal homomeric and heteromeric receptors. In this review, we have selected heteromeric nAChRs as the target and comment on literature reports of the past five years dealing with the discovery of new small molecule ligands or the advanced pharmacological/preclinical investigation of more promising compounds. The results obtained with bifunctional nicotinic ligands and a light-activated ligand as well as the applications of promising radiopharmaceuticals for heteromeric subtypes are also discussed.
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Affiliation(s)
- Carlo Matera
- Department of Pharmaceutical Sciences, Medicinal Chemistry Section "Pietro Pratesi", University of Milan, Via Luigi Mangiagalli 25, 20133 Milan, Italy
| | - Claudio Papotto
- Department of Pharmaceutical Sciences, Medicinal Chemistry Section "Pietro Pratesi", University of Milan, Via Luigi Mangiagalli 25, 20133 Milan, Italy
| | - Clelia Dallanoce
- Department of Pharmaceutical Sciences, Medicinal Chemistry Section "Pietro Pratesi", University of Milan, Via Luigi Mangiagalli 25, 20133 Milan, Italy
| | - Marco De Amici
- Department of Pharmaceutical Sciences, Medicinal Chemistry Section "Pietro Pratesi", University of Milan, Via Luigi Mangiagalli 25, 20133 Milan, Italy.
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Elgoyhen AB. The α9α10 acetylcholine receptor: a non-neuronal nicotinic receptor. Pharmacol Res 2023; 190:106735. [PMID: 36931539 DOI: 10.1016/j.phrs.2023.106735] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/06/2023] [Accepted: 03/14/2023] [Indexed: 03/17/2023]
Abstract
Within the superfamily of pentameric ligand-gated ion channels, cholinergic nicotinic receptors (nAChRs) were classically identified to mediate synaptic transmission in the nervous system and the neuromuscular junction. The α9 and α10 nAChR subunits were the last ones to be identified. Surprisingly, they do not fall into the dichotomic neuronal/muscle classification of nAChRs. They assemble into heteropentamers with a well-established function as canonical ion channels in inner ear hair cells, where they mediate central nervous system control of auditory and vestibular sensory processing. The present review includes expression, pharmacological, structure-function, molecular evolution and pathophysiological studies, that define receptors composed from α9 and α10 subunits as distant and distinct members within the nAChR family. Thus, although α9 and α10 were initially included within the neuronal subdivision of nAChR subunits, they form a distinct clade within the phylogeny of nAChRs. Following the classification of nAChR subunits based on their main synaptic site of action, α9 and α10 should receive a name in their own right.
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Affiliation(s)
- Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Vuelta de Obligado 2490, Buenos Aires 1428, Argentina.
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3
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Schiffers I, Frings M, Kübber BM, Truong KN, Rissanen K, Bolm C. Preparation of Enantiopure 3-Aminopiperidine and 3-Aminoazepane Derivatives from Ornithine and Lysine. Consecutive Syntheses of Pharmacologically Active Analogs, Such as Besifloxacin. Org Process Res Dev 2022. [DOI: 10.1021/acs.oprd.2c00152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ingo Schiffers
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Marcus Frings
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Britta Maria Kübber
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Khai-Nghi Truong
- Department of Chemistry, University of Jyvaskyla, P.O. Box 35, Survontie 9B, FI-40014 Jyväskylä, Finland
| | - Kari Rissanen
- Department of Chemistry, University of Jyvaskyla, P.O. Box 35, Survontie 9B, FI-40014 Jyväskylä, Finland
| | - Carsten Bolm
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
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Elgoyhen AB. The α9α10 nicotinic acetylcholine receptor: a compelling drug target for hearing loss? Expert Opin Ther Targets 2022; 26:291-302. [PMID: 35225139 PMCID: PMC9007918 DOI: 10.1080/14728222.2022.2047931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Hearing loss is a major health problem, impacting education, communication, interpersonal relationships, and mental health. Drugs that prevent or restore hearing are lacking and hence novel drug targets are sought. There is the possibility of targeting the α9α10 nicotinic acetylcholine receptor (nAChR) in the prevention of noise-induced, hidden hearing loss and presbycusis. This receptor mediates synaptic transmission between medial olivocochlear efferent fibers and cochlear outer hair cells. This target is key since enhanced olivocochlear activity prevents noise-induced hearing loss and delays presbycusis. AREAS COVERED The work examines the α9α10 nicotinic acetylcholine receptor (nAChR), its role in noise-induced, hidden hearing loss and presbycusis and the possibility of targeting. Data has been searched in Pubmed, the World Report on Hearing from the World Health Organization and the Global Burden of Disease Study 2019. EXPERT OPINION The design of positive allosteric modulators of α9α10 nAChRs is proposed because of the advantage of reinforcing the medial olivocochlear (MOC)-hair cell endogenous neurotransmission without directly stimulating the target receptors, therefore avoiding receptor desensitization and reduced efficacy. The time is right for the discovery and development of α9α10 nAChRs targeting agents and high throughput screening assays will support this.
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Affiliation(s)
- Ana Belén Elgoyhen
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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Thompson MJ, Baenziger JE. Structural basis for the modulation of pentameric ligand-gated ion channel function by lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183304. [DOI: 10.1016/j.bbamem.2020.183304] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/20/2020] [Accepted: 04/05/2020] [Indexed: 10/24/2022]
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Sadahiro M, Demars MP, Burman P, Yevoo P, Zimmer A, Morishita H. Activation of Somatostatin Interneurons by Nicotinic Modulator Lypd6 Enhances Plasticity and Functional Recovery in the Adult Mouse Visual Cortex. J Neurosci 2020; 40:5214-5227. [PMID: 32467358 PMCID: PMC7329312 DOI: 10.1523/jneurosci.1373-19.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 01/27/2023] Open
Abstract
The limitation of plasticity in the adult brain impedes functional recovery later in life from brain injury or disease. This pressing clinical issue may be resolved by enhancing plasticity in the adult brain. One strategy for triggering robust plasticity in adulthood is to reproduce one of the hallmark physiological events of experience-dependent plasticity observed during the juvenile critical period: to rapidly reduce the activity of parvalbumin (PV)-expressing interneurons and disinhibit local excitatory neurons. This may be achieved through the enhancement of local inhibitory inputs, particularly those of somatostatin (SST)-expressing interneurons. However, to date the means for manipulating SST interneurons for enhancing cortical plasticity in the adult brain are not known. We show that SST interneuron-selective overexpression of Lypd6, an endogenous nicotinic signaling modulator, enhances ocular dominance plasticity in the adult primary visual cortex (V1). Lypd6 overexpression mediates a rapid experience-dependent increase in the visually evoked activity of SST interneurons as well as a simultaneous reduction in PV interneuron activity and disinhibition of excitatory neurons. Recapitulating this transient activation of SST interneurons using chemogenetics similarly enhanced V1 plasticity. Notably, we show that SST-selective Lypd6 overexpression restores visual acuity in amblyopic mice that underwent early long-term monocular deprivation. Our data in both male and female mice reveal selective modulation of SST interneurons and a putative downstream circuit mechanism as an effective method for enhancing experience-dependent cortical plasticity as well as functional recovery in adulthood.SIGNIFICANCE STATEMENT The decline of cortical plasticity after closure of juvenile critical period consolidates neural circuits and behavior, but this limits functional recovery from brain diseases and dysfunctions in later life. Here we show that activation of cortical somatostatin (SST) interneurons by Lypd6, an endogenous modulator of nicotinic acetylcholine receptors, enhances experience-dependent plasticity and recovery from amblyopia in adulthood. This manipulation triggers rapid reduction of PV interneuron activity and disinhibition of excitatory neurons, which are known hallmarks of cortical plasticity during juvenile critical periods. Our study demonstrates modulation of SST interneurons by Lypd6 to achieve robust levels of cortical plasticity in the adult brain and may provide promising targets for restoring brain function in the event of brain trauma or disease.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/physiology
- Animals
- Dominance, Ocular/genetics
- Evoked Potentials, Visual/genetics
- Evoked Potentials, Visual/physiology
- Female
- GPI-Linked Proteins/genetics
- GPI-Linked Proteins/physiology
- Immunohistochemistry
- Interneurons/physiology
- Male
- Mice
- Mice, Knockout
- Mice, Transgenic
- Neuronal Plasticity/genetics
- Neuronal Plasticity/physiology
- Phosphatidylinositols/pharmacology
- Receptors, Nicotinic/genetics
- Recovery of Function/genetics
- Somatostatin/physiology
- Vision, Monocular/genetics
- Vision, Monocular/physiology
- Visual Acuity/genetics
- Visual Cortex/physiology
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Affiliation(s)
- Masato Sadahiro
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Michael P Demars
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Poromendro Burman
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Priscilla Yevoo
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Andreas Zimmer
- Institute of Molecular Psychiatry, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Hirofumi Morishita
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
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Wang J, Blasio A, Chapman HL, Doebelin C, Liaw V, Kuryatov A, Giovanetti SM, Lindstrom J, Lin L, Cameron MD, Kamenecka TM, Pomrenze MB, Messing RO. Promoting activity of (α4) 3(β2) 2 nicotinic cholinergic receptors reduces ethanol consumption. Neuropsychopharmacology 2020; 45:301-308. [PMID: 31394567 PMCID: PMC6901472 DOI: 10.1038/s41386-019-0475-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/18/2019] [Accepted: 07/19/2019] [Indexed: 12/19/2022]
Abstract
There is increasing interest in developing drugs that act at α4β2 nicotinic acetylcholine receptors (nAChRs) to treat alcohol use disorder. The smoking cessation agent varenicline, a partial agonist of α4β2 nAChRs, reduces alcohol intake, but its use can be limited by side effects at high therapeutic doses. There are two stoichiometric forms of α4β2 nAChRs, (α4)3(β2)2 and (α4)2(β2)3. Here we investigated the hypothesis that NS9283, a positive allosteric modulator selective for the (α4)3(β2)2 form, reduces ethanol consumption. NS9283 increased the potency of varenicline to activate and desensitize (α4)3(β2)2 nAChRs in vitro without affecting other known targets of varenicline. In male and female C57BL/6J mice, NS9283 (10 mg/kg) reduced ethanol intake in a two-bottle choice, intermittent drinking procedure without affecting saccharin intake, ethanol-induced incoordination or ethanol-induced loss of the righting reflex. Subthreshold doses of NS9283 (2.5 mg/kg) plus varenicline (0.1 mg/kg) synergistically reduced ethanol intake in both sexes. Finally, despite having no aversive valence of its own, NS9283 enhanced ethanol-conditioned place aversion. We conclude that compounds targeting the (α4)3(β2)2 subtype of nAChRs can reduce alcohol consumption, and when administered in combination with varenicline, may allow use of lower varenicline doses to decrease varenicline side effects.
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Affiliation(s)
- Jingyi Wang
- Departments of Neuroscience and Neurology, The University of Texas at Austin, Austin, TX, USA.
| | - Angelo Blasio
- 0000 0004 1936 9924grid.89336.37Departments of Neuroscience and Neurology, The University of Texas at Austin, Austin, TX USA
| | - Holly L. Chapman
- 0000 0004 1936 9924grid.89336.37Departments of Neuroscience and Neurology, The University of Texas at Austin, Austin, TX USA
| | - Christelle Doebelin
- 0000000122199231grid.214007.0Department of Molecular Medicine, The Scripps Research Institute, Scripps Florida, Jupiter, FL USA
| | - Victor Liaw
- 0000 0004 1936 9924grid.89336.37Departments of Neuroscience and Neurology, The University of Texas at Austin, Austin, TX USA
| | - Alexander Kuryatov
- 0000 0004 1936 8972grid.25879.31Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
| | - Simone M. Giovanetti
- 0000 0004 1936 9924grid.89336.37Departments of Neuroscience and Neurology, The University of Texas at Austin, Austin, TX USA
| | - Jon Lindstrom
- 0000 0004 1936 8972grid.25879.31Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
| | - Li Lin
- 0000000122199231grid.214007.0DMPK core, The Scripps Research Institute, Scripps Florida, Jupiter, FL USA
| | - Michael D. Cameron
- 0000000122199231grid.214007.0DMPK core, The Scripps Research Institute, Scripps Florida, Jupiter, FL USA
| | - Theodore M. Kamenecka
- 0000000122199231grid.214007.0Department of Molecular Medicine, The Scripps Research Institute, Scripps Florida, Jupiter, FL USA
| | - Matthew B. Pomrenze
- 0000 0004 1936 9924grid.89336.37Departments of Neuroscience and Neurology, The University of Texas at Austin, Austin, TX USA
| | - Robert O. Messing
- 0000 0004 1936 9924grid.89336.37Departments of Neuroscience and Neurology, The University of Texas at Austin, Austin, TX USA
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Norleans J, Wang J, Kuryatov A, Leffler A, Doebelin C, Kamenecka TM, Lindstrom J. Discovery of an intrasubunit nicotinic acetylcholine receptor-binding site for the positive allosteric modulator Br-PBTC. J Biol Chem 2019; 294:12132-12145. [PMID: 31221718 DOI: 10.1074/jbc.ra118.006253] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 06/19/2019] [Indexed: 11/06/2022] Open
Abstract
Nicotinic acetylcholine receptor (nAChR) ligands that lack agonist activity but enhance activation in the presence of an agonist are called positive allosteric modulators (PAMs). nAChR PAMs have therapeutic potential for the treatment of nicotine addiction and several neuropsychiatric disorders. PAMs need to be selectively targeted toward certain nAChR subtypes to tap this potential. We previously discovered a novel PAM, (R)-7-bromo-N-(piperidin-3-yl)benzo[b]thiophene-2-carboxamide (Br-PBTC), which selectively potentiates the opening of α4β2*, α2β2*, α2β4*, and (α4β4)2α4 nAChRs and reactivates some of these subtypes when desensitized (* indicates the presence of other subunits). We located the Br-PBTC-binding site through mutagenesis and docking in α4. The amino acids Glu-282 and Phe-286 near the extracellular domain on the third transmembrane helix were found to be crucial for Br-PBTC's PAM effect. E282Q abolishes Br-PBTC potentiation. Using (α4E282Qβ2)2α5 nAChRs, we discovered that the trifluoromethylated derivatives of Br-PBTC can potentiate channel opening of α5-containing nAChRs. Mutating Tyr-430 in the α5 M4 domain changed α5-selectivity among Br-PBTC derivatives. There are two kinds of α4 subunits in α4β2 nAChRs. Primary α4 forms an agonist-binding site with another β2 subunit. Accessory α4 forms an agonist-binding site with another α4 subunit. The pharmacological effect of Br-PBTC depends both on its own and agonists' occupancy of primary and accessory α4 subunits. Br-PBTC reactivates desensitized (α4β2)2α4 nAChRs. Its full efficacy requires intact Br-PBTC sites in at least one accessory and one primary α4 subunit. PAM potency increases with higher occupancy of the agonist sites. Br-PBTC and its derivatives should prove useful as α subunit-selective nAChR PAMs.
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Affiliation(s)
- Jack Norleans
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Jingyi Wang
- Department of Neuroscience, University of Texas at Austin, Austin, Texas 78712
| | - Alexander Kuryatov
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Abba Leffler
- Neuroscience Graduate Program, Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York 10010
| | - Christelle Doebelin
- Department of Molecular Medicine, The Scripps Research Institute, Scripps, Florida, Jupiter, Florida 33458
| | - Theodore M Kamenecka
- Department of Molecular Medicine, The Scripps Research Institute, Scripps, Florida, Jupiter, Florida 33458
| | - Jon Lindstrom
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104.
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Hone AJ, McIntosh JM. Nicotinic acetylcholine receptors in neuropathic and inflammatory pain. FEBS Lett 2017; 592:1045-1062. [PMID: 29030971 DOI: 10.1002/1873-3468.12884] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/22/2017] [Accepted: 10/05/2017] [Indexed: 01/11/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are actively being investigated as therapeutic targets for the treatment of pain and inflammation, but despite more than 30 years of research, there are currently no FDA-approved analgesics that are specific for these receptors. Much of the initial research effort focused on the α4β2 nAChR subtype, but more recently, additional subtypes have been identified as promising new leads and include α6β4, α7, and α9-containing nAChRs. This Review will focus on the distribution of these nAChRs in the cell types involved in neuropathic pain and inflammation and the activity of currently available nicotinic ligands.
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Affiliation(s)
- Arik J Hone
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | - J Michael McIntosh
- Department of Biology, University of Utah, Salt Lake City, UT, USA.,Department of Psychiatry, University of Utah, Salt Lake City, UT, USA.,George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, USA
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Sparling BA, DiMauro EF. Progress in the discovery of small molecule modulators of the Cys-loop superfamily receptors. Bioorg Med Chem Lett 2017; 27:3207-3218. [DOI: 10.1016/j.bmcl.2017.04.073] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 04/20/2017] [Accepted: 04/24/2017] [Indexed: 12/11/2022]
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11
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Wang ZJ, Deba F, Mohamed TS, Chiara DC, Ramos K, Hamouda AK. Unraveling amino acid residues critical for allosteric potentiation of (α4)3(β2)2-type nicotinic acetylcholine receptor responses. J Biol Chem 2017; 292:9988-10001. [PMID: 28446611 DOI: 10.1074/jbc.m116.771246] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/20/2017] [Indexed: 01/29/2023] Open
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are promising drug targets to manage several neurological disorders and nicotine addiction. Growing evidence indicates that positive allosteric modulators of nAChRs improve pharmacological specificity by binding to unique sites present only in a subpopulation of nAChRs. Furthermore, nAChR positive allosteric modulators such as NS9283 and CMPI have been shown to potentiate responses of (α4)3(β2)2 but not (α4)2(β2)3 nAChR isoforms. This selective potentiation underlines that the α4:α4 interface, which is present only in the (α4)3(β2)2 nAChR, is an important and promising drug target. In this report we used site-directed mutagenesis to substitute specific amino acid residues and computational analyses to elucidate CMPI's binding mode at the α4:α4 subunit extracellular interface and identified a unique set of amino acid residues that determined its affinity. We found that amino acid residues α4Gly-41, α4Lys-64, and α4Thr-66 were critical for (α4)3(β2)2 nAChR potentiation by CMPI, but not by NS9283, whereas amino acid substitution at α4His-116, a known determinant of NS9283 and of agonist binding at the α4:α4 subunit interface, did not reduce CMPI potentiation. In contrast, substitutions at α4Gln-124 and α4Thr-126 reduced potentiation by CMPI and NS9283, indicating that their binding sites partially overlap. These results delineate the role of amino acid residues contributing to the α4:α4 subunit extracellular interface in nAChR potentiation. These findings also provide structural information that will facilitate the structure-based design of novel therapeutics that target selectively the (α4)3(β2)2 nAChR.
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Affiliation(s)
- Ze-Jun Wang
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363
| | - Farah Deba
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363
| | - Tasnim S Mohamed
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363
| | - David C Chiara
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Kara Ramos
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363
| | - Ayman K Hamouda
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363, .,Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Sciences Center, Bryan, Texas 77807, and
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12
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Windley MJ, Vetter I, Lewis RJ, Nicholson GM. Lethal effects of an insecticidal spider venom peptide involve positive allosteric modulation of insect nicotinic acetylcholine receptors. Neuropharmacology 2017; 127:224-242. [PMID: 28396143 DOI: 10.1016/j.neuropharm.2017.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/28/2017] [Accepted: 04/06/2017] [Indexed: 01/17/2023]
Abstract
κ-Hexatoxins (κ-HXTXs) are a family of excitotoxic insect-selective neurotoxins from Australian funnel-web spiders that are lethal to a wide range of insects, but display no toxicity towards vertebrates. The prototypic κ-HXTX-Hv1c selectively blocks native and expressed cockroach large-conductance calcium-activated potassium (BKCa or KCa1.1) channels, but not their mammalian orthologs. Despite this potent and selective action on insect KCa1.1 channels, we found that the classical KCa1.1 blockers paxilline, charybdotoxin and iberiotoxin, which all block insect KCa1.1 channels, are not lethal in crickets. We therefore used whole-cell patch-clamp analysis of cockroach dorsal unpaired median (DUM) neurons to study the effects of κ-HXTX-Hv1c on sodium-activated (KNa), delayed-rectifier (KDR) and 'A-type' transient (KA) K+ channels. 1 μM κ-HXTX-Hv1c failed to significantly inhibit cockroach KNa and KDR channels, but did cause a 30 ± 7% saturating inhibition of KA channel currents, possibly via a Kv4 (Shal-like) action. However, this modest action at such a high concentration of κ-HXTX-Hv1c would indicate a different lethal target. Accordingly, we assessed the actions of κ-HXTX-Hv1c on neurotransmitter-gated ion channels in cockroach DUM neurons. We found that κ-HXTX-Hv1c failed to produce any major effects on GABAA or glutamate-Cl receptors but dramatically slowed nicotine-evoked ACh receptor (nAChR) current decay and reversed nAChR desensitization. These actions occurred without any alterations to nAChR current amplitude or the nicotine concentration-response curve, and are consistent with a positive allosteric modulation of nAChRs. κ-HXTX-Hv1c therefore represents the first venom peptide that selectively modulates insect nAChRs with a mode of action similar to the excitotoxic insecticide spinosyn A. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Monique J Windley
- School of Life Sciences, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Irina Vetter
- Institute for Molecular Bioscience, University of Queensland, Brisbane St. Lucia, QLD 4072, Australia; School of Pharmacy, University of Queensland, Brisbane St. Lucia, QLD 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, University of Queensland, Brisbane St. Lucia, QLD 4072, Australia
| | - Graham M Nicholson
- School of Life Sciences, University of Technology Sydney, Broadway, NSW 2007, Australia.
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13
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Wang J, Lindstrom J. Orthosteric and allosteric potentiation of heteromeric neuronal nicotinic acetylcholine receptors. Br J Pharmacol 2017; 175:1805-1821. [PMID: 28199738 DOI: 10.1111/bph.13745] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 01/30/2017] [Accepted: 02/06/2017] [Indexed: 12/16/2022] Open
Abstract
Heteromeric nicotinic ACh receptors (nAChRs) were thought to have two orthodox agonist-binding sites at two α/β subunit interfaces. Highly selective ligands are hard to develop by targeting orthodox agonist sites because of high sequence similarity of this binding pocket among different subunits. Recently, unorthodox ACh-binding sites have been discovered at some α/α and β/α subunit interfaces, such as α4/α4, α5/α4 and β3/α4. Targeting unorthodox sites may yield subtype-selective ligands, such as those for (α4β2)2 α5, (α4β2)2 β3 and (α6β2)2 β3 nAChRs. The unorthodox sites have unique pharmacology. Agonist binding at one unorthodox site is not sufficient to activate nAChRs, but it increases activation from the orthodox sites. NS9283, a selective agonist for the unorthodox α4/α4 site, was initially thought to be a positive allosteric modulator (PAM). NS9283 activates nAChRs with three engineered α4/α4 sites. PAMs, on the other hand, act at allosteric sites where ACh cannot bind. Known PAM sites include the ACh-homologous non-canonical site (e.g. morantel at β/α), the C-terminus (e.g. Br-PBTC and 17β-estradiol), a transmembrane domain (e.g. LY2087101) or extracellular and transmembrane domain interfaces (e.g. NS206). Some of these PAMs, such as Br-PBTC and 17β-estradiol, require only one subunit to potentiate activation of nAChRs. In this review, we will discuss differences between activation from orthosteric and allosteric sites, their selective ligands and clinical implications. These studies have advanced understanding of the structure, assembly and pharmacology of heteromeric neuronal nAChRs. LINKED ARTICLES This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc.
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Affiliation(s)
- Jingyi Wang
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Jon Lindstrom
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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14
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Jain A, Kuryatov A, Wang J, Kamenecka TM, Lindstrom J. Unorthodox Acetylcholine Binding Sites Formed by α5 and β3 Accessory Subunits in α4β2* Nicotinic Acetylcholine Receptors. J Biol Chem 2016; 291:23452-23463. [PMID: 27645992 DOI: 10.1074/jbc.m116.749150] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Indexed: 11/06/2022] Open
Abstract
All nicotinic acetylcholine receptors (nAChRs) evolved from homomeric nAChRs in which all five subunits are involved in forming acetylcholine (ACh) binding sites at their interfaces. Heteromeric α4β2* nAChRs typically have two ACh binding sites at α4/β2 interfaces and a fifth accessory subunit surrounding the central cation channel. β2 accessory subunits do not form ACh binding sites, but α4 accessory subunits do at the α4/α4 interface in (α4β2)2α4 nAChRs. α5 and β3 are closely related subunits that had been thought to act only as accessory subunits and not take part in forming ACh binding sites. The effect of agonists at various subunit interfaces was determined by blocking homologous sites at these interfaces using the thioreactive agent 2-((trimethylammonium)ethyl) methanethiosulfonate (MTSET). We found that α5/α4 and β3/α4 interfaces formed ACh binding sites in (α4β2)2α5 and (α4β2)2β3 nAChRs. The α4/α5 interface in (β2α4)2α5 nAChRs also formed an ACh binding site. Blocking of these sites with MTSET reduced the maximal ACh evoked responses of these nAChRs by 30-50%. However, site-selective agonists NS9283 (for the α4/α4 site) and sazetidine-A (for the α4/β2 site) did not act on the ACh sites formed by the α5/α4 or β3/α4 interfaces. This suggests that unorthodox sites formed by α5 and β3 subunits have unique ligand selectivity. Agonists or antagonists for these unorthodox sites might be selective and effective drugs for modulating nAChR function to treat nicotine addiction and other disorders.
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Affiliation(s)
- Akansha Jain
- From the Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Alexander Kuryatov
- From the Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Jingyi Wang
- the Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, and
| | - Theodore M Kamenecka
- the Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, Florida 33458
| | - Jon Lindstrom
- From the Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104,
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15
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Indurthi DC, Lewis TM, Ahring PK, Balle T, Chebib M, Absalom NL. Ligand Binding at the 4-4 Agonist-Binding Site of the 42 nAChR Triggers Receptor Activation through a Pre-Activated Conformational State. PLoS One 2016; 11:e0161154. [PMID: 27552221 PMCID: PMC4995024 DOI: 10.1371/journal.pone.0161154] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/01/2016] [Indexed: 11/18/2022] Open
Abstract
The α4β2 nicotinic acetylcholine receptor (nAChR) is the most abundant subtype in the brain and exists in two functional stoichiometries: (α4)3(β2)2 and (α4)2(β2)3. A distinct feature of the (α4)3(β2)2 receptor is the biphasic activation response to the endogenous agonist acetylcholine, where it is activated with high potency and low efficacy when two α4-β2 binding sites are occupied and with low potency/high efficacy when a third α4-α4 binding site is occupied. Further, exogenous ligands can bind to the third α4-α4 binding site and potentiate the activation of the receptor by ACh that is bound at the two α4-β2 sites. We propose that perturbations of the recently described pre-activation step when a third binding site is occupied are a key driver of these distinct activation properties. To investigate this, we used a combination of simple linear kinetic models and voltage clamp electrophysiology to determine whether transitions into the pre-activated state were increased when three binding sites were occupied. We separated the binding at the two different sites with ligands selective for the α4-β2 site (Sazetidine-A and TC-2559) and the α4-α4 site (NS9283) and identified that when a third binding site was occupied, changes in the concentration-response curves were best explained by an increase in transitions into a pre-activated state. We propose that perturbations of transitions into a pre-activated state are essential to explain the activation properties of the (α4)3(β2)2 receptor by acetylcholine and other ligands. Considering the widespread clinical use of benzodiazepines, this discovery of a conserved mechanism that benzodiazepines and ACh potentiate receptor activation via a third binding site can be exploited to develop therapeutics with similar properties at other cys-loop receptors.
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Affiliation(s)
| | - Trevor M. Lewis
- School of Medical Sciences, University of NSW, Kensington, NSW, 2052, Australia
| | | | - Thomas Balle
- Faculty of Pharmacy, University of Sydney, NSW, 2006, Australia
| | - Mary Chebib
- Faculty of Pharmacy, University of Sydney, NSW, 2006, Australia
- * E-mail: (NLA); (MC)
| | - Nathan L. Absalom
- Faculty of Pharmacy, University of Sydney, NSW, 2006, Australia
- * E-mail: (NLA); (MC)
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